Structural framework systems

ABSTRACT

A structural framework system for the construction of exhibition display stands and the like makes use of a beam extrusions having dovetail shaped edge formations which enable panel frames to be hung therefrom and locked in position by virtue of coupling frames incorporating therein a locking element which can be retracted into a recess of the coupling frame for initial location of the coupling frame relative to a beam and can then be moved to project from the recess and to clamp the beam dovetail by insertion of actuating pins into bores provide in the coupling frame and communicating with the recess. A beam end fitting enables a beam to be secured to a transversely-extending second beam by a similar process and a 4-way node fitting enable nodes to be formed at the intersection of a plurality of orthogonal beams. A leg length adjustment provides for the adjustment of the lengths of structural support legs. A fabric roof may be attached to the framework system by virtue of a foot secured along the fabric edge being received in a shoe provided in the framework.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to structural framework systems such as may beutilized in the construction of prefabricated buildings or temporary andsemi-permanent structures, for example display stands at exhibitions andshowroom accommodation.

2. Background Art

Current framework construction systems are either crude, likescaffolding, making them difficult to waterproof, or require manyspecific components for various situations. Moreover, few systems havethe flexibility to accommodate multi-storey or bespoke layouts with fullreusability and fast assembly.

Aluminum frame structures conveniently rely heavily on screw-threadedfasteners, but aluminum itself is too soft to maintain a durable threadthereby forcing the use of rivet-on nuts and other steel threaded insertsystems. Such systems require delicate use in often onerous conditions.When they fail in use such systems are very difficult if not impossibleto repair.

It is thus an object of the present invention to provide a relocatablestructure system in which the above mentioned disadvantages are overcomeor at least substantially reduced.

BRIEF SUMMARY OF THE INVENTION

According to the present invention in one of the aspects there isprovided a structure system where a linkage between individual framemembers is effected using a pressed-in actuating element to position andhold a locking catch into a mating linear feature.

In one preferred embodiment of the present invention which is describedin detail hereinafter, mating features of interconnectable frame membersare formed as extruded parts and are effective symmetrically as adovetailed joint, enabling connections to be made from two orthogonaldirections. In one component of the described structure system themating dovetail features occur at a chamfer angle at the vertices of asubstantially square beam section such that panels or further beams areattachable to continue any of the orthogonal surface planes of the beam,such attachment being effected by hooking a feature of the furtherstructural member to one side of the beam dovetail and engaging thelocking catch on the other side of the beam dovetail by operation of aplurality of spaced apart actuating elements.

In the abovementioned embodiment the actuating elements comprise pinswhich are locatable in respective recesses in the further structuralmember for engaging upon movement into the recess a moveable catchelement which moves to lock the parts together. Conveniently, theactuating elements are elongate tapered pins having a high-helix,multi-start, low-profile surface protrusion and a head formed to enablerotation of the pin, for example by means of a hex tool. The high helixtopography causes the pins to rotate as they are tapped home and thenensures that they cannot be accidentally extracted. To remove a pin, atool is used to rotate it by a partial turn and the rotation of thehelix profile causes the pin to be slightly extracted. Because it istapered, once the pin is a little loose it can be readily removed.

The recess into which the actuating pin extends communicates with arecess adapted to accommodate the catch element which is preferablygenerally L-shaped in cross-section and is arranged so that, when theactuating pin is not in place, the catch element can be retractedsubstantially into its accommodating recess so as to be inoperative and,when the actuating pin is inserted, the catch element is moved so as toproject from the recess for engaging another of the interconnectableframe members to lock the two together. The catch member can include asurface complementary to and engageable by the actuating pin to effectoperation of the catch, or alternatively the catch can be formed of arelatively soft material such as aluminum which can be deformed bycoaction with a harder material actuating pin.

The dovetail joint can advantageously include a weather seal located inone of its mating surfaces to seal the connection. An annular weatherseal can also be provided in the recess for the actuating pin to sealthe actuating pin once it is fully inserted into its recess.

Construction beams used in the structure system of the present inventionare conveniently of a hollow rectangular box section having internalwebs to add strength to the beam. End blanking components are attachableto the ends of the beam and the blanking components can advantageouslyhave complementary mating features to allow connection of the blankedoff end of a beam with the dovetail feature of a further beam extendingtransversely thereto. Similar 4-way crown components enable nodes to beformed by the joining of plural beam ends.

Preferably, infill pads formed of blastomeric material for example aremountable on either side of a junction between frame members to seal thejunction and render it waterproof.

The invention extends furthermore to an adjustment system enabling legstructures to be adjusted in length. In a hereinafter describedembodiment of this aspect of the invention a frame member is providedwith a circular bore within which a selectively adjustable tubular legis mounted. Wedges are provided which can be adjusted to secure orrelease the tube in dependence upon the adjustment of a securing ring,and the surfaces of the wedges which bear on the tubular leg areprovided with screw thread sections which can impress a complementarythread on the tubular leg thereby enabling the leg length to be adjustedin a precision manner by relative rotation.

The system of the present invention also extends to an interlocking“shoe” and “foot” arrangement for securing a fabric roof relative to abuilding structure or the like, and the roof fabric being attached at oradjacent its edge to an elongate foot extrusion which is insertable intoan elongate shoe extrusion formed on or secured to the buildingstructure. A toe region of the foot is preferably curved upwardly toengage in a recess below a holding lip of the shoe and a heel of thefoot is held in an undercut provided at the heel of the shoe.Preferably, the foot and shoe interconnection is such as to include twoheel structures, one behind the other.

Structures formed in accordance with the teachings of the presentinvention preferably employ extruded aluminum beams, widely regarded inthe building industry as the most cost effective material forlightweight structures. Although basically modular, the system isflexible enough to permit a wide variety of support and spans, enablingstructures to be tailored into specific forms previously only attainablewith premium bespoke solutions. These can include features likebalconies, atrium and elevated walkways. The structure system isintegrally designed with its own structural platform flooring systemwhich is able to accommodate onerous ground topologies. This minimisesthe need for site preparation. However, as described hereinafterattention is given to the need to apply ballast to hold structures downand a self leveling soft ground support system is also utilised. Roofingintegration permits either usable upper platform space or large spantruss frameworks. The relocatable structure system of the presentinvention proposes a linking system that allows full interchangeabilitybetween beams, floor panels, wall panels, roof panels or modules at allorthogonal angles. However, other angles are possible.

The above and further features of the present invention are set forth inthe appended claims and will be described hereinafter by reference toexemplary embodiments which are illustrated in the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section view of an extruded beam embodying theinvention and showing one panel section in course of assembly to thebeam and two other panel sections already assembled, the panel sectionsincluding frame extrusions adapted to couple with the beam.

FIGS. 2A and 2B are perspective views from two different directionsshowing orthogonally connected beams as in FIG. 1 having facing (wall)and floor panels coupled and in course of being coupled thereto as inFIG. 1.

FIG. 3 is a perspective view of one end of the beam of FIG. 1 andfurther shows an end fitting connector piece adapted to be fitted to theend of the beam to enable the beam to be clamped to a further beamextending transversely.

FIG. 4A is a perspective view showing two beams joined together by thearrangement of FIG. 3 and further showing a node construction, FIG. 4Bis a perspective view of a 4-way coupling port enabling avertically-extending beam to have four horizontally-extending beamsaffixed thereto as shown in FIG. 4A, and FIG. 4C shows a bracingelement.

FIG. 5 is a cross-sectional view of an adjustable leg fitting embodyingthe present invention with the parts shown in a fully tightened positionon the left hand side of the figure and in a loosened position on theright hand side of the figure.

FIG. 6 is a cross-sectional view of an exemplary arrangement accordingto the present invention for attaching a fabric roof to a buildingstructure.

FIG. 7 is a view similar to FIG. 6 in which the foot and shoeinterconnection has a double heel structure.

FIG. 8 is a cross-sectional view of the interconnection of FIG. 7 formedas part of an extruded gutter arrangement.

FIG. 9A is a perspective view showing an exemplary roof structureconstructed according to the teachings of the present invention.

FIG. 9B is a part sectional end view of part of the roof structure ofFIG. 9A.

FIG. 10 is a perspective view showing the coupling together of two beamsections.

DETAILED DESCRIPTION OF THE INVENTION

Referring more specifically to the drawings, FIG. 1 shows across-sectional view of an elongate support beam 1 having connectedthere to a plurality of wall or floor sections which extend indirections substantially perpendicular to the beam 1. The beam 1 isformed or extruded aluminum with a substantially rectangularcross-section and has extending longitudinally of the beam at eachcorner 2 thereof a symmetrical curvilinear dovetail formation 5, setchamfer-like at an angle of 45° to the external surfaces 3, 4respectively of beam 1.

An extruded aluminum coupling frame 6 is arranged to support a panel 7,a wall or flooring or roof panel for example, to be assembled to thebeam 1, and has a hook shape connector part 8 complementary to thedovetail 5 so that the panel coupling frame 6 can be “hung” on thedovetail 5 as shown in FIG. 1 at top left. Projecting dovetail part 9has a convex outer surface 10 and the coupling frame 6 has acomplementary concave surface 11 against which surface 10 of thedovetail 9 fits in use as shown at top and bottom right in FIG. 1. Thesurface 11 culminates in a projecting nose portion 12 and there is anelongate recess 13 on the reverse side of nose portion 12. Thecomplementary shapes of the dovetail formation 5 and the co-operatingpart of the coupling frame 6 are completed by surface 23 of the frame 6which rests upon dovetail surface portion 24 extending from the concavesurface portion 22 when the frame 6 is close coupled with the beam 1.

An elongate, generally rounded L-shaped locking element 15 is located inrecess 13 and in operation pivots in the recess as describedhereinafter. A circular cross-section, tapered bore 16 communicates withthe recess 13 and has a portion 17 of increased radial dimension at itsopening 18. A seal 19 is located in the portion 17. The elongate lockingelement 15 is an aluminum extrusion which fits loosely into the recess13 and can be pivoted about the end of its shorter limb 14 between theposition shown at top left in FIG. 1 where it is substantially whollycontained within the recess and the position shown at top and bottomright in FIG. 1 where the longer limb 21 of the element 15 protrudesfrom the recess 13 and engages under the projecting dovetail part 9 ofbeam 1.

To effect such pivotal movement of the locking element 15, an elongatetapered pin 20 having a high-helix, multi-start, low-profile screwthreaded surface protrusion (not shown) and a head having a hex toolcompliant socket 25 is introduced through opening 18 into the bore 16and is tapped down into the bore by use of a soft mallet. The pininterferes with the locking element 15 as it is driven in and causes theelement 15 to pivot so as to lock the coupling frame 6 onto the dovetailformation 5 on the beam 1. Pins 20 are driven into bores 16 at pluralspaced-apart locations along the length of the coupling frame extrusion6. The pins prevent reverse rotation of the locking element 15 andensure that the structure remains fixed under compressive preload.

From the foregoing it will be appreciated that the present inventionresides in the provision of a base member, such as the beam 1 of FIG. 1,having formations such as to enable a conforming member, such as thecoupling frame 6 of FIG. 1, to be clamped thereto by a simple operationcomprising the insertion of elements, such as the pins 20, which actuatea clamping mechanism, such as the locking element 15, so as to couplethe two parts together. The conforming member has external featuresenabling it to act at a hanger from the base member and has internalfeatures enabling it to retain the elongate rolling wedge locking memberextrusion. Bores 16 for the pins 20 are located at spaced apartintervals along the elongate coupling frame 6 and are drilled to acceptthe locking pins 20. The bores 16 can be drilled with the locking member15 inserted into recess 13 and opened to its locking position such thatthe bores will partially intersect with the locking member and therebyincrease the surface area on the locking member that will interact withthe pins when they are inserted. Alternatively, the bores can be drilledwithout the locking member present in which case the pins would deformthe locking member in use.

In use, the parts are initially brought together with the lockingelement 15 in its retracted position within its recess 13 such that thecoupling frame 6 closely engages with the dovetail formation on the beam1. The tapered locking pins 20 are then inserted and tapped home. As thepins 20 enter into bores 16 they rotate or otherwise displace thelocking element 15 such that its limb 21 is caused to extend out of therecess 13 and act against the underside of the dovetail formation on thebeam 1 thereby pulling the joint together. The locking pins 20 onceinserted remain wedged between the locking element and coupling frameextrusions, but can be loosened and extracted by being turned with a keyengaged with the hex head 21.

Instead of tapered pins 20, discrete wedge channels may be milled orotherwise prepared to accept wedge shaped inserts. These would actsubstantially as the pins in displacing the locking element to interlockwith the dovetail. Also the dovetail formation may comprise severalsmaller dovetail barbs in each direction, rather than just one largebarb. The rolling wedge locking element would then also have aconforming section able to interact effectively with the multi-barbeddovetail design.

The coupling frame extrusions 6 are designed to accept floor, wall orroof panels. The coupling frame 6 can be mitred to act as a rigid frameto a panel infill, or left loose so that the panels can “float” toaccommodate fit tolerances and thermal expansion. In this latterinstance the unimpeded coupling frame 6 will lock fully to the dovetailon the beam extrusion 1, acting as a rigid extension of the beam whichthen traps and holds the infill panel 7.

FIGS. 2A and 2B show perspective views from different directions of anarrangement wherein orthogonal beams provide support for facing (wall)and floor panels, the beams being as shown in FIG. 1 and the panelsbeing supported by frame extrusions as shown in FIG. 1. The means forinterconnecting the beams will be described hereinafter with referenceto FIG. 3, but from FIGS. 2A and 2B it can readily be seen how thesystem of the invention provides for panelling to be applied to aframework structure. Note that in FIGS. 2A and 2B the wall panel 7′ andthe floor panel 7″ are not fully in place.

As shown in FIG. 3, beam end fittings 32 are arranged to be fitted intothe ends of beams 1 as described hereinbefore so that the support axisis orthogonal to the beam 1, thus enabling a beam end to be coupled tothe side of a transverse second beam. Beam end fitting 32 is shown inFIG. 3 to comprise a head portion 33 which has a cross-sectional shapesubstantially the same as that of the support frames 6 shown in FIG. 1and functions in the same manner as regards the clamping of the headportion to a dovetail formation of a riser beam 1. Depending from headportion 33 is a flat plate 34 having a plurality of flanges 35 extendingsubstantially perpendicularly from the rear thereof, the flanges 35being arranged to fit closely to the upper and lower faces 4 of the beam1 on the inside of the beam box section and above and below the webs 30of the beam when the fitting 32 is fitted into the open end of the beam.The fitting 32 can be designed to be retained by virtue of being aninterference fit into the open end of a beam 1 or could be retained byadhesive or by means of appropriately inserted fixing screws. It will benoted that the upper and lower faces 4 of the beam 1 at the end thereofinto which the fitting 32 is to be fitted can be cut back (as shownclearly at 40 in FIG. 3) to enable the flat plate 34 of the fitting 32to lie flush with the beam end. It will further be noted that the beam 1has a slotted formation 41 at the centre of each of its faces and thatslots 37 are cut into the fitting 32 so that it clears these formations.The purpose of the formations 41 will be explained later.

The end fittings 32 are very economical to produce by extrusion, eventhough some final machining is necessary to cut the slots 37 and formthe bores 16 for the pins 20 which actuate the locking element 15. Thebasic extrusion has merely to be cut into short sections defining theend fittings prior to their final machining and drilling. Similar endfittings could be formed by casting and equivalent angled end fittingsenabling a beam end to be coupled to the side of another beam as anangle other than 90° thereto could also be formed by casting.

FIG. 4A of the accompanying drawings shows how end fittings as describedwith reference to FIG. 3 can be utilized to couple the end of one beamto the side of a second, transversely extending beam. FIG. 4A also showshow nodes can be formed by use of a 4-way end fitting which replicatesthe beam fitting 32 of FIG. 3 in four directions. Referring to FIG. 4A,there is shown on the left thereof a beam 1 which is affixedtransversely to the side of a second beam 1′ by means of an end fitting32 as hereinbefore described. FIG. 4A further shows the end of the beam1′ coupled to a node defined at the end of yet another beam 1″ extendingtransversely to the beam 1′ and also shows two other beams coupled tothe beam 1″ in similar manner to the beam 1′ but extending therefrom indifferent directions, the beam opposite to beam 1′ being shown not fullyin position.

FIG. 4B shows a 4-way node fitting 45 coupled to the end of a riser beam1″ as in FIG. 4A. The node fitting 45 is formed of cast aluminum and hasfour sections 46 which replicate the dovetail edge formations of thebeam 1″ but in transverse directions and four sections 47 which continuethe dovetail edge formations of the beam in the same direction. Each ofthe transverse dovetail sections 46 enables the coupling of a beam endto the end of beam 1″ by use of an end fitting 32 as described withreference to FIG. 3. On the reverse of the crown-like neck fitting 45,spigot components (not shown) are provided which are adapted to befitted into the open end of riser beam 1″, similarly to the action offitting the end fitting 32, and enable the node fitting 45 to beretained to the beam end either as an interference fit or by means ofadhesive and/or appropriately positioned screws. As shown, the nodefitting 45 has a central opening 48 which passes right through thefitting to support the bussing of services or to act as a drainagechannel for example.

Elastomeric seal blocks 49 are shown in FIG. 4A fitted at the corners ofthe beam 1″ and serve to fill the spaces that otherwise would existbetween the beam 1″ and the beams beam 1′ coupled thereto. The blocks 49are shaped to engage with the dovetail edge formations of the beam 1″.The seal blocks 49 can advantageously be made slightly oversize so thatthey can also act as compliant positioning pads to locate the beam endconnector fittings 32 which, to provide for some compliance in thesetting of the beams in their nodes, can be dimensioned so as to becapable of moving a little along the junction dovetail defined by thesections 46, within limits defined by the elastomeric seal blocks. Theelastomeric seal blocks fit into each upper vertex of the cubic node andserve the purpose of providing a weather seal through the permittedrange of compliance. The joint will be naturally self centering.

Where coupling frame extrusions 6 are used to retain infill panels ashereinbefore described, elastomeric seal blocks 49 may be employed tofill the spaces otherwise occurring between the connected parts when thesystem design does not lend itself to being neatly mitred. FIGS. 2A and2B illustrate this. Here again the seal blocks can act to provide selfcentering with compliance and weather sealing.

A further weather seal 54 can be fitted into a recess provided for thispurpose in the hook shaped connector part 8 of the coupling frame 6 asshown in FIG. 1. A similar provision can be made in the beam end fitting32 as shown in FIG. 3. This seal could alternatively be provided in thedovetail edge formations of the beam 1. In conjunction with theelastomeric seal blocks 49 abovementioned, the seal strips 54 can ensurecomplete weather sealing of a structure without need for on-sitepatching of joints and edges which is not only time consuming but alsois unsightly.

It was mentioned in connection with the description of FIG. 3 that thebeam extrusions 1 were formed on each surface 3, 4 thereof with aslotted formation 41. The purpose of this formation is to enablelocating and/or strengthening elements to be incorporated when, forexample, a multi-storey structure is constructed which includes nodeconfigurations such as shown in FIG. 4A wherein the beam 1″ isvertically extending and the lower end of a second vertically-extendingbeam is supported on the node. FIG. 4C is a perspective view of anexemplary bracing element 50 in the form of a metal plate shaped as aright-angled triangle with a cut-out at its 90° apex and with T-shapedformations along its adjacent edges complementary to the slottedformation 41 provided in the beams. It will readily be appreciated thatthe lower edge of the bracing element 50 can be slid into the formation41 of the right-hand beam of FIG. 4A and located so that when thevertical beam of FIG. 4B is set down upon the FIG. 4A node, the verticaledge of the bracing element 50 can be engaged into the formation 41 ofthe descending FIG. 4B beam. If this is done for all the horizontalbeams of the node, the FIG. 4B beam will be positively located withrespect to the node. The bracing element 50 could readily be arranged tobe locked in position by means of locking wedges or screw fasteners forexample.

Sliders capable of being locked into the slotted formations 41 andhaving parts protruding therefrom could have other applications andcould be introduced into the formations either from the beam ends or bya local spoiling of the formations enabling the slider to be inserted.Such sliders could have fastener compliant extensions protruding fromthe formations 41 so that sliders installed in both horizontal beams andvertical risers can be arranged to mate and be secured to each other.

Where vertical riser beams need to be supported rigidly orthogonal tohorizontal beams to provide necessary structural stability, trusses canbe employed and might, for example, extend diagonally between oppositeinternal corners of a rectangular frame segment comprised of two riserbeams and two horizontal beams. As required for local support, or iffull anti-paralleling stability is required when the trusses are onlytensile members such as tightened cables, two such trusses can connectopposite corners such that they cross in the centre. The trusses can befixed into the comers using the bracing element 50 abovementioned orother slider components. If separate slider components havingoverlapping features are used and the truss has a further overlappingfeature, a single pin or fastener can be employed not only to lock theslider components to each other but also to attach the truss.

The invention also provides for the adjustment of the lengths ofstructural support legs constituted for example by vertical riser beamssuch as the beam 1″ shown in FIG. 4A so as to enable a structure to bereadily erected on uneven ground. Hereinafter described is an adjustablelength fitting which could be adapted to fit into the open end of ariser beam extrusion as illustrated in FIG. 5, or, in otherconfigurations, could be incorporated as part of the 4-way crown fitting45 of FIG. 4B for example.

As shown in FIG. 5 one such adjustable length fitting includes acircumferential array of spaced-apart radial double wedge elements60(a), 60(b) nationally describing an open tube adjustable diameter independence upon the circumferential spacing apart of the wedge elements.The radially outer surfaces 62 of the wedge elements are chamfered to afine taper angle and the inner surfaces carry screw thread profiles. Thewedges are split axially with gaps 63 between them. Flat radiallyextending sides 60(c) of the wedges are separated by small elastomericpads 64 which serve to bias the split wedge parts apart from each other.Instead of elastomeric pads, the radial wedges can include a featuredesigned to locate an expanding spring.

A support 65 is designed to be attached to other constructionalfixtures, for example into the open lower end of a riser beam 1″ ashereinbefore described and as shown in FIG. 5. The support 65 has aninner cylindrical bore 66 which features a chamfer taper conforming tothe upper parts of the wedges 60. The taper surface 66 and the tapersurfaces of the wedges can advantageously be provided with a lowfriction surface. A screw thread 67 is provided on radially outersurface 68 of the support 65 and an internally screw threaded securingring 69 is engaged with screw thread 67 to enable the axial position ofthe securing ring to be adjusted relative to the support 65.

The securing ring 69 acts as a nut and has an inwardly facing flange 70which coacts with an annular compression part 71 to determine thecondition of the wedge 60. The compression part 71 has a wedgeconforming taper 72 which engages the lower wedge surfaces of the wedges60 and further has an array of tongues or keys (not shown) which extendinto the circumferential gaps between the wedge elements 60(a), 60(b) soas to permit the wedge array as a whole to be engaged and rotated by thecompression part 71. Both the securing ring 69 and the compression part71 have outwardly facing contours (not shown) designed to promotegripping by hand or tool for the purpose or enabling rotation of thesame.

When the unit is assembled, the sprung array of wedge elements 60(a),60(b) are installed in the radial compression part 71 with the tonguesor keys abovementioned located circumferentially between the wedgeelements. The securing ring 69 is then installed over the. compressionpart 71 and screw threadingly engaged with the support fitting 65. Aplain tubular leg 61 is then inserted through the inner cylindrical boreof the assembly. The tubular strut 61 has a diameter a little smallerthan the expanded wedge system thereby allowing the leg 61 to slidefreely through the fitting for course length adjustment. As the securingring 69 is tightened onto the support 65, the conforming wedge facescompress the wedge 60 until it bears upon the leg 61.

Although the bearing pressure of the wedge 60 on the leg 61 is modestthe internal thread of the wedge elements 60(a), 60(b) bear upon thesofter metal of the leg 61 (for example hardened steel againstaluminum), so that the wedges elastically deform the strut and forge amating screw thread counterpart on the outer surface of the strut. Inthis state of compression, the compression part 71 (with its tongues orkeys located between the circumferentially spaced wedge segments) actsas a captive nut enabling the leg 61 to be rotated through the fitting65, thereby increasing or reducing the effective length of the leg.

In use, load exerted on the strut will tend to tighten the wedge arrayin proportion thereto, further ensuring a firm grip. An unambiguousmetal to metal connection then exists to rigidly lock the leg 61 to thesupport 65.

In an alternative embodiment, instead of two tapered wedge faces on thearray members only a single wedge face is employed, the other face beingflat. In this case, the support 65 no longer compresses radially, butonly axially. The radial compression of the wedge parts is solelyeffected by the compression part 71 and securing ring 69. This optionmitigates friction when compression part 71 is employed as a nut, but atthe expense of some clamping leverage.

The tubular legs 61 can stand on their own weight distribution padswhere conditions allow. However, in soft conditions, a more effectivemethod of weight distribution is to provide for connecting strutsbetween the ground bases of the support legs wherever sinkage could be aproblem. In this event an extrusion profile is determined with a largedownwardly facing surface area optionally with features arranged toinhibit lateral sliding. The beam accepts end plugs which can slidetelescopically into either or both of the beam ends, thereby enablingthe beam length to freely adjust over a small range. The end plugs arein turn attached to the support leg bases with a pivoting and rotatingjoint such as a ball and socket, so that the ground beams need not lieorthogonally to the main framework system. They can thereby adjust inlength and angle to better follow the prevailing ground topology. Theupward face of the ground extrusion usefully has features enablingadditional braces to be attached wherein required between itself and thelevelled off floor beams.

The constructional system hereinbefore described makes use ofsymmetrical beam sections which enable infill panels to be fitted toeither or both sides of a beam. This is advantageous where the structurecannot be retained relative to the ground with appropriate fastenings sothat it proves necessary to provide ballast, especially on tallmulti-storey structures. In this case infill panels may be installedwhere appropriate into the bottom of the base floor frame cells. Asuitable large mass such as a large concrete slab may then be droppedinto the frame to be supported by the bottom infill panel. A top infillpanel can then be installed as before, creating in essence a very heavyfloor panel.

Although principally described as an orthogonally modular structuresystem, the present invention could be implemented with extrusionsestablishing different holding angels for infill panels and differentnode and beam and hanger angles. This would cause floor plans includingtriangles and other polygons to become possible. Likewise, walls neednot rise vertically, or roof and floor modules be always horizontal.

There are many instances when it is necessary to join a flexible fabricskin to a rigid frame such as may be formed from the beam structuredisclosed with reference to FIG. 1 to 5 to form an adequate roof withappropriate tensioning of the roof fabric. The coupling of the rooffabric to the frame must be flexible, waterproof and readily fitted andremoved. There are several established methods available but all havedrawbacks. Lacing and buckling systems are difficult to seal. Ropewelded into a pocket at the edge of a fabric and then slid into anextrusion with a narrow continuous opening is difficult to fit andimpossible to fit as a continuous band. Other bespoke systems utilizingextruded wedge elements which rotate to trap a suitably expanded fabricedge can jam and are not easily adjusted to balance fabric tension. Itis thus a further feature of the present invention that a means isprovided which overcomes or at least substantially reduces theseproblems in a neat and effective manner. The concept is to provide anextruded “foot” at the fabric edge and an extruded slip-on “shoe” in thestructure arranged to receive the “foot”.

Referring to FIG. 6, an exemplary “foot” and “shoe” arrangement 80comprises an extruded aluminum shoe 80 defining a recessed footreceiving area 82 bounded to its forward (toe) end by a lip 83. Theinternal surface 84 of recess 82 curves away from the lip 83, mergingwith an elongate flat base surface 85 which terminates in a heel part 86of the shoe having a surface 87 which is inwardly directed towards thelip 83 to define a retaining undercut heel 88 of the foot 90. The shoeis otherwise open at 89 for receiving foot 90 therein.

The foot 90 is a further extrusion and has an external surface shapewhich is substantially complementary to the internal shape of the shoewith an enlarged bulbous toe portion 93, a slightly inwardly curvedbottom surface 98, and a rounded heel 88. The foot 90 also comprises amajor flat planar top surface 91 to which there is attached in anysuitable manner, such as by gluing, chemical bonding or riveting forexample, an elongate edge of a roof fabric 92.

When the foot 90 is inserted into the shoe opening 89, the toe portion93 enters into the recess 82 below the lip 83 and moves forwardly toengage the forward end of the recess. Curved upper portion 95 of the topof the foot 90 is received in an undercut 96 of curved inner surface 97of the lip 83 to assist in preventing unwanted release of the foot 90from the shoe 81 once the foot is fully within the shoe. The elongatecurved under surface 98 has the effect of reducing the thickness of thefoot and thereby increasing its resilience to enable the heel 88 of thefoot to pass inwardly-directed upper edge 99 of the shoe. As the foot 90is moved into the shoe 81, it is pivoted clockwise about the toereceiving region of the shoe so that the heel 88 of the foot 90 movessimultaneously into the heel portion 86 of the shoe and slides back tocontact the inner surface 87 of the heel 86 with a complementary fitwhich ensures that it cannot pull out when the fabric 92 is tensioned.

Because of the distance between toe and heel, the coupling referred toabove need only be rotated by a small angle to allow the heel to engage.This makes fitting easier but also consequently is susceptible to easyrelease. The longitudinal plane of the shoe needs to be arranged at anangle such that it is always steeper than the steepest expected fabrictension vector, or the heel could inadvertently become disengaged. Adisadvantage of a long foot is the increased risk that it may deformunder tension to an extent sufficient for the toe to be released fromunder the shoe lip. For operational reasons it is helpful for the footextrusion to be as flexible as possible, but if it is too flexible, thisrisk is further increased. Consideration also needs to be given to thetemperature operating range because suitably plasticised thermoplasticsmaterials soften significantly when warned and may as a result causeuncoupling of the joint. A typical preferred material for the footextrusion would be plasticiser PVC which is available in a wide range ofelasticities.

FIG. 7 shows the roofing fabric 92 attached to a foot 90 which isinserted into a shoe 81 with the toe 93 under the lip 83 in analternative construction in which two heels are engaged rather than justthe one. In this configuration, outer heel 100 holds a proportion of thetension in the fabric and provides an extended tongue against which toattach the fabric thereby improving the attachment therebetween. Theinner heel 88 of the foot 90 then holds the remaining tension. The riskof the toe flexing sufficiently to disengage from the lip is lower thanin the preceding embodiment for the same foot length because the toe toinner heel separation is significantly reduced leaving less materialavailable for flexing. This also enables a relatively more flexibleextrusion and/or a higher maxi8mum operating temperature. This variantrequires a greater degree of rotation of the shoe to engage the toe.While this requires more slack on the fabric in order to fit the shoe,it also provides more positive retention of the foot in the shoe andhence of the fabric relative to the base structure. Successive stages inthe mating of the foot in the shoe are shown in FIG. 7 in dotted linesat 101(a), 101(b), 101(c), 101(d) and 101(e).

In both embodiments, where applied as part of a roofing system there isa benefit to integrate the shoe extrusion 81 with a gutter as shown inFIG. 8 where 102 represents a shoe/gutter extrusion, 92 is the fabricand 90 is the foot as in FIG. 6. The gutter may be a removable separateextrusion as shown or equally may be extruded as an integral part of amain frame member serving as a roof beam. Aluminum is a suitablematerial for such extrusions. As well as providing for a drainagechannel, a gutter elevates the coupling above any likely water build up.This is important at any non-linear joint between adjacent fabricsections, such as with a square roof or anywhere where it is notfeasible to run the shoe extrusion seamlessly around a corner. Theresulting gap in the corner can be covered by a local valance whichdrops below the coupling level.

It is helpful for the end of the heel profile of the shoe to continueinto a soft radius as shown in FIG. 8 at 103 to support the fabric 92 asit rotates to its natural tension vector. This mitigates any unnaturallocal fabric wear and stressing.

If it is necessary to have a highly flexible extrusion for packingpurposes namely to enable the roof fabric to be packed for ease oftransportation, and/or of run around tight profiles, or otherwise tosustain high tension forces and/or high temperatures, mono axialstiffeners can be used. These could for example make the form of pins orstaples running from heel to toe through the body of the foot extrusion.This would present the extrusion from flexing to such a degree as todisengage the toe without compromising the linear axis flexibility.

Therefore, there has been described a system which requires only that aflexible plastic extrusion is welded or bonded to the edge of thefabric, and a mating form included in the rigid frame extrusion.Alternatively the mating extrusion can be on a separate attached gutter.As aforementioned this concept as akin to an extruded foot profileattached to the fabric and an extruded slip on shoe formed into theframe or gutter. To fit the system, the foot is rotated such that thetoe can fit under the upper lip of the shoe and, the heel can then dropdown and fit into the heel of the shoe. The toe is retained by the lipand the fabric tension vector then holds the heel engaged. Mere loss oftension without sufficient rotation to disengage the heel is notsufficient to release the coupling. the effectiveness of the heel couldbe improved by providing it with undercut features such as a hook orbarb. In this case the shoe would have to be a little longer to permitthe foot to move in far enough to clear the undercut in the heel. Thefoot then moves back as the heel fully engages.

FIG. 9A is a perspective view showing an exemplary structure wherein avertical riser has four horizontally-extending beams coupled to itsupper end by means of a 4-way node fitting 45 as hereinbefore describedwith reference to FIG. 4B being secured to the riser, and end fittings32, as hereinbefore described with reference to FIG. 3, being fitted tothe cooperating ends of the horizontal beams. Additionally shown in FIG.9 is the use of aluminum extrusions 200 comprising a first portion 201defining a shoe for receiving a foot affixed to the edge of a fabricroof as described hereinbefore with reference to FIG. 7 and a secondportion 202 adapted to be released secured to the dovetail edgeformations of the horizontal beams by the same means as were describedhereinbefore with reference to FIG. 1 for fixing coupling frames 6 tothe beams. It will be seen from FIG. 9A that a neat and attractive rooffinish can be obtained with the riser furthermore serving to drain waterfrom the roof through the central opening of a 4-way node fitting 45.The use of elastomeric sealing blocks 49 as hereinbefore described withreference to FIG. 4A can also be seen in FIG. 9A.

FIG. 9B shows more clearly the construction of the top lefthand cornerof cross-beam of FIG. 9A. The roofing fabric 92 is shown attached tofoot 90 which in turn is located in the shoe/gutter extrusion 102mounted on and locked relative to beam 1 in the manner described hereinwith reference for example to FIG. 1.

FIG. 10 shows that the two extruded beam sections as hereinbeforedescribed with reference to FIG. 1 can readily be joined together bymeans of a first extrusion 250 adapted to locate between the juxtaposeddovetail projections at the juxtaposed edges of the two beams as shownand a second extrusion 260 adopted to overlie the juxtaposed beam edgesas shown and to be secured to the first extrusion 250 by means of fixingscrews 270.

The invention having been described in the foregoing by reference toparticular embodiments, it is to be well understood that the embodimentsare exemplary only and that the modifications and variations can be madewithout departure from the spirit and scope of the appended claims. Forexample, whilst the curved dovetail profile of the beam edge featuresshown in FIG. 1 is presently preferred, other shapes would be possiblewhich would enable a complementary shaped panel frame extrusion, beamend fitting or 4-way node fitting to be utilized substantially in themanner herein described. Additionally, in a modification of thearrangement described with reference to FIGS. 6 to 9 for securing afabric roof the “shoe” could be fitted to the fabric and the “foot”attached to the structure. Furthermore, whilst the pins 20 have beendescribed in the foregoing as being tapped into the ir accommodatingrecesses 16 using a soft mallet, their helical topography does enablethem to be turned (screwed) into position. Additionally, in FIGS. 2A and2B some of the panel frame sections 67 are shown as open extrusionsrather than as solid extrusions and this is a possibility which savesmaterial and may be advantageous, at least from a cost basis, insituations where the high strength of a solid extrusion is notnecessary.

What is claimed is:
 1. A structural system comprising: a first componenthaving a first formation; a second component having a second formationcomplementary to said first formation, said first and second componentsbeing interconnectable by virtue of said first and second formations; arecess formed in said second component; a locking element included insaid second component moveable in said recess between an operativeposition and an inoperative position; and an actuating element mountedon said second component, said actuating element moveable relative tosaid locking element so as to move the locking element out of saidrecess to engage said first formation to lock said first component andsecond component together.
 2. A system as claimed in claim 1, whereinsaid actuating element comprises a member insertable into a secondrecess in said second component, said second recess communicating withsaid first recess, wherein insertion of said member drives the lockingelement out of said first recess.
 3. A system as claimed in claim 1,wherein said member comprises a tapered pin and said second recess istapered.
 4. A system as claimed in claim 3, wherein said pin has anexternal screw thread formation and means enabling said pin to be turnedby means of a tool.
 5. A system as claimed in claim 4, wherein saidscrew thread formation is a multi-start, low-profile, helical surfaceprotrusion.
 6. A system as claimed in claim 1, wherein the action ofsaid actuating element moves said locking element toward said secondformation to enable said first formation to be clamped between saidlocking element and said second formation.
 7. A system as claimed inclaim 6, wherein said second formation is hooked so as to enable saidsecond component to be hooked onto said first formation pendingoperation of said locking element by said actuating element to securesaid first and second components together.
 8. A system a claimed inclaim 7, wherein said first formation is generally dovetail-shaped.
 9. Asystem as claimed in claim 1, wherein said first component comprises anelongate beam having said first formation extending along the lengththereof.
 10. A system as claimed in claim 9, wherein said beam isrectangular in cross-section and has said first formation extendingalong the length of each of the four edges thereof.
 11. A system asclaimed in claim 10, wherein said formations are generally inclinedsurfaces along the edges of the beam.
 12. A system as claimed in claim 9or 10 or 11, wherein said beam is hollow.
 13. A system as claimed inclaim 12, further comprising strengthening webs within said beam.
 14. Asystem as claimed in claim 13, wherein said beam comprises and aluminumextrusion.
 15. A system as claimed in claim 9, wherein said secondcomponent comprises a panel frame member enabling an edge of a panel tobe secured to said beam.
 16. A system as claimed in claim 9, whereinsaid second component comprises a beam end fitting enabling an edge of afirst beam to be secured to a side of a transversely extending secondbeam.
 17. A system as claimed in claim 16, further comprising a nodefitting enabling a plurality of beam ends provided with beam endfittings to be secured together on said node fitting with the differentbeams extending in different directions.
 18. A system as claimed inclaim 17, wherein said node fitting is adapted to be secured to an endof a riser beam so as to enable a plurality of transverse beams to becoupled orthogonally thereto.
 19. A system as claimed in claim 17 or 18,wherein said node fitting is apertured to for serving as a drainagepassageway or for conveying service utilities through the node.
 20. Asystem as claimed in claim 18, further comprising adjustment means foradjusting the length of said riser beam.
 21. A system as claimed inclaim 20, wherein said adjustment means comprises a telescopicarrangement including an adjustable diameter clamping arrangementenabling the telescopic parts to be clamped in an adjusted position. 22.A system as claimed in claim 21, wherein said adjustable diameterclamping arrangement comprises a plurality of circumferentiallyspaced-apart wedge elements and adjustable means acting upon said wedgeelements to determine their radial positions.
 23. A system as claimed inclaim 22, wherein said adjustable means comprises an adjusting ringscrew-threadedly engaged with an outer part of said telescopicarrangement and adjustable to cause said wedge elements to move relativeto an inclined surface of said outer part and thereby undergoradially-directed movement.
 24. A system as claimed in claim 22 or 23wherein the radially innermost surfaces of said wedge elements areformed with portions of screw threads and means are engaged with saidwedge elements for enabling their rotation in unison within saidadjusting ring for effecting fine adjustment of said telescopicarrangement.
 25. A system as claimed in claim 1, further comprisingmeans for attaching a fabric sheet to a frame member of the system. 26.A system as claimed in claim 25, wherein the fabric sheet has anextruded formation attached thereto at or adjacent an edge thereof andsaid frame member has a complementary-shaped formation such as toreceive said extruded formation and to retain the same under the tensionof the fabric sheet.
 27. A system as claimed in claim 26, wherein saidextruded formation formed on said fabric sheet is generally in the formof a foot and said complementary-shaped formation is generally in theform of a slip-on shoe for said foot.
 28. A system as claimed in claim27, wherein said foot and said shoe have a plurality of interengageableheel portions.
 29. A structure constructed by use of a system as claimedin claim
 1. 30. A structural system as claimed in claim 1, furthercomprising means for securing a fabric sheet to a structural member ofthe structural system, said fabric sheet having an edge formationextending along or adjacent an edge thereof and said structural memberhaving a complementary formation to said edge formation engageable withsaid edge formation, one of said edge and complementary formations beingsubstantially in the form of a foot and the other being substantially inthe form of a slip-on shoe for said foot, wherein once said edge andcomplementary formations are engaged, tension in said fabric sheetserves to retain said edge and complementary formations in the engagedcondition.